Institute for Powertrains and
Automotive Technology
Getreidemarkt 9
A-1060 Vienna
http://www.ifa.tuwien.ac.at
Univ.-Prof. Dr. Dipl.-Ing.
Bernhard GERINGER
Director
A-1060 Vienna, Getreidemarkt 9
Tel.: ++43-1/58801-31500
Fax: ++43-1/58801-31599
[email protected]
http://www.ifa.tuwien.ac.at
„Meta-analysis for an E20/25 technical development
study - Task 2: Meta-analysis of E20/25 trial reports
and associated data“
Final Report
Authors:
Prof. Dr. Bernhard Geringer
Dipl.-Ing. Johann Spreitzer
Dipl.-Ing. Mattias Mayer
Dipl.-Ing. Christian Martin
I
Preamble
The following preamble is a brief overview of the expectations and conclusions which
can be drawn from the present work. The main focus is done on a detailed
consideration of the ethanol content between 15% and 25% (named E20/25 in this
study). To get a comprehensive overview of the effects of ethanol as a blending
component, higher mixing rates were examined with a comprehensive meta-analysis
too (up to 100 % ethanol).
It should be noted, however, that the current study represents an actual state of
currently available global literature and do not reflect specific directly done research
results on this field. The vehicles and engines investigated in the literature sources
are mostly production engines available on the market and were used for the
combustion of ethanol, but were usually not optimized for E20/25. In summary there
is a variety of different boundary conditions in the individual studies, therefore
comparability is limited for some cases. Therefore, the literature was selected
according to specific criteria, to create comparative conditions across all the studies.
Furthermore, it should be noted that in addition to the current E10 (10 % ethanol
blend rate) vehicles and the specially adapted flexible fuel vehicles (FFV) which allow
operation up to an ethanol concentration of 85%, neither vehicles specifically
designed nor produced for the range of E20/25 are currently available. In addition to
extensive modifications in the engine control software (motor electronics) further
adjustments to mixture formation, ignition, fuel circuit and material adaptation need to
be made to the engine corresponding to the higher ethanol content in the fuel.
With 1st September 2014 the EURO 6 emission standard for type approval for
passenger car and light duty trucks comes into effect, registration and sale for new
types of vehicles are following on 1st January 2015. During the study EURO 6
engines were only sporadically available on the market. For this engines however,
there are no scientific studies regarding E20/25. Therefore, no EURO 6 vehicles are
considered in this study.
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II
Table of Contents
Preamble ..................................................................................................................... I
Table of Contents ....................................................................................................... II
Abbreviation............................................................................................................... III
Executive Summary .................................................................................................... V
1
Motivation ............................................................................................................ 1
2
Meta-Analysis ...................................................................................................... 1
2.1
3
4
Methodology .................................................................................................. 1
Basics for usage of alternative fuels in SI engines .............................................. 5
3.1
Increasing the efficiency by “Downsizing” ...................................................... 5
3.2
Influence of Ethanol on RON (Knock-Resistance) ......................................... 7
3.3
Alternative fuels for gasoline engines .......................................................... 10
Results from the meta-analysis ......................................................................... 15
4.1
Fuel Consumption and Energy-Efficiency.................................................... 15
Specific Fuel Consumption (SFC) ..................................................................... 15
4.2
Emissions .................................................................................................... 19
4.2.1
CO2 emissions ...................................................................................... 20
4.2.2
CO emissions........................................................................................ 22
4.2.3
HC emissions ........................................................................................ 24
4.2.4
NOx emissions ...................................................................................... 26
4.2.5
Particle emissions ................................................................................. 28
4.2.6
Efficiency............................................................................................... 32
4.3
Brazil ........................................................................................................... 33
5
Conclusion and further topics to be investigated ............................................... 34
6
Annex ................................................................................................................ 36
7
Literature ........................................................................................................... 37
7.1
Literature for the meta-analysis ................................................................... 37
7.2
Further literature .......................................................................................... 54
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III
Abbreviation
ASTM
American Society for Testing and Materials
BMEP
Break mean effective pressure
BSFC
Brake specific fuel consumption
C
Cylinder
C2H2
Acetylene
C6H6
Benzene
CA°bTDC
Crank angle before top dead centre
CADC
Common Artemis Driving Cycles
CARB
California Air Resources Board
CH4
Methane
CO
Carbon monoxide
CO2
Carbon dioxide
COV
Coefficient of variance
CR
Compression ratio
CVS
Constant volume sampling
DI
Direct injection
DIN
German Institute for Standardization
DOHC
Double overhead camshaft
DOI
Duration of injection
ECE15
Urban Driving Cycle of the NEDC
ECU
Engine control unit
EPA
Environmental Protection Agency
FC
Fuel consumption
FFV
Flexible fuel vehicles
FID
Flame ionization detector
FSN
Filter smoke number
FTIR
Fourier transform infrared spectroscopy
FTP
Federal Test Procedure
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IV
H2O
Water vapour
IMEP
Indicated mean effective pressure
ISFC
Indicated specific fuel consumption
MBT
Maximum break torque
MON
Motor Octane Number
MPI
Multi point injection
NA
Naturally aspirated
NEDC
New European Driving Cycle
NMHC
Non-methane hydrocarbons
NMOG
Non-methane organic gas
NONMHC
Non-oxygenated non-methane hydrocarbons
NOx
Nitrogen oxide
OBD
On-board diagnostics
PAH
Polycyclic aromatic hydrocarbon
PFI
Port fuel injection
PM
Particulate matter
PN
Particle number
RON
Research Octane Number
RVP
Reid vapour pressure
SFC
Specific fuel consumption
SI
Spark ignition
SOHC
Single overhead camshaft
SOI
Start of injection
TC
Turbo charged
THC
Total hydrocarbons
TWC
Three-way catalyst
US06
Supplemental Federal Test Procedure (SFTP)
VVA
Variable valve actuation
WOT
Wide Open Throttle
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V
Executive Summary
In this study, the Institute for Powertrains and Automotive Technology, Vienna
University of Technology, has collected a variety of literature sources on the subject
of ethanol blends. The focus of this study is on ethanol blending rates from 15% to
25%. For a better understanding of the influence of ethanol on fuel consumption and
emissions, ethanol blends have been considered up to 100% ethanol additional. This
study does not cover evaluation of evaporative emissions from the fuel tank system
or the compatibility of plastics with ethanol.
In a first step, the selection of literature according to the PRISMA (see chapter 2.1)
scheme was made. Studies that have been found to be relevant were used for the
meta-analysis. The main focus of this analysis was the influence of the ethanol
content in the fuel on the following parameters:

Specific fuel consumption (fuel consumption based on the generated engine
power)

Efficiency

CO2 emissions

CO emissions

HC emissions

NOx emissions

Particle emissions
The summary is based on a scientific analysis of an established literature review and
presents the current state of research, which has general (global) validity. The
different studies have different boundary conditions, which are not necessarily explicit
in the literature. The literature was selected following criteria to create comparative
conditions. No optimised E20/25 production vehicles exist, thus limiting meaningful
insights at the moment. But previous experience do not show any fundamental
problems, considering that the provided materials and control algorithms of the
engine electronics are designed to operate this ethanol content. The technologies
investigated in the studies are vehicles from serial production and engines which are
adapted for the engine test bench. At the time the study was conducted only a few
EURO 6 engines were available. However, no scientific studies regarding E20/25
have been carried out for those engines so far.
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VI
The results of the meta-analysis confirm the physical explanations. In particular, the
results obtained from the study for E20/25 are in the respective trend from E5 to
E100. The most important results of the meta-analysis are as follows:

Influence of E20/25 on specific fuel consumption
With E20/25 the over all specific fuel consumption increases about 3% in
average.

Influence of E20/25 on engine efficiency
For E20/25 the thermodynamic efficiency (energy based) increases by 5% in
average.

Influence of E20/25 on CO2 emissions
The CO2 end-of-pipe emissions decrease by about 2% for E20/25 in average.

Influence of E20/25 on CO emissions
Generally the CO engine-out emissions decrease by up to 10% in average
and the CO end-of-pipe emissions decrease by about 20% in average for
E20/25.

Influence of E20/25 on HC emissions
The HC engine-out emissions are also reduced by about 10% for E20/25 in
average. The HC end-of-pipe Emissions decrease by about 5% for E20/25 in
average.

Influence of E20/25 on NOx emissions
The NOx engine-out emissions increase for E20/25 by 20% in general. The
NOx end-of-pipe emissions are equivalent to E0.

Influence of E20/25 on Particle emissions
The Particle emissions have to be investigated further. In general there is the
ability to decrease the particle emissions with E20/25.
The engine-out emissions give a good overview of the effects of ethanol on the
combustion. This allows the evaluation of the combustion quality and the advantages
of the used fuel. On the contrary, the end-of-pipe emissions show the emissions that
are emitted into the environment. The reason for this is the exhaust aftertreatment
system, which is located between the engine and the exhaust pipe. This is used to
reduce the engine-out emissions so far thus the emission regulations are complied.
A summary of these results especially for E20/25 compared to E0 can be seen in
Figure 0-1.
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VII
Figure 0-1: Results from the meta-analysis for E20/25 vs. E0
In addition to the results shown above, the addition of ethanol as a splash blend
(admixture of different ethanol contents without changing the base fuel) increases the
RON of the fuel. The higher knock resistance achieved in this way for E20/25-fuels
offers the possibility to optimise the design of the engine (compression ratio) and thus
increase the efficiency. But this assumes that only E20/25 or higher blending rates
are used. The full exploitation of the ethanol/fuel potential therefore requires that the
engines are only operated with the applied fuel (eg: E20/25). If you are forced to
operate the engine with different fuels, the full theoretical potential of the fuel cannot
be used. Exemplary the problem of bivalent vehicles (vehicles able to run on different
fuels) should be mentioned here, such as vehicles that run on gasoline and CNG
have shown.
As the studies evaluated for the meta-analysis have shown, especially for the use of
E20/25 for internal combustion engines the following gaps could be identified:

Particle emissions:
In general there is the ability to decrease the particle emissions with E20/25.
But it is essential to optimize the engine for higher ethanol contents.

Optimized engines for E20/25
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VIII
At the present time, no studies specifically for E20/25 optimized engines are
available. The vehicles used in these studies were mainly for E20/25 capable
cars. In order to realize the full potential of E20/25 an optimization of the
engine operation is necessary.

EURO 6 engines (passenger cars & light duty trucks)
No study specifically for EURO 6 vehicles with regard to ethanol fuel is
presently available. However, some studies show that particulate emissions
can be significantly reduced using an appropriate motor design for ethanol
fuels. This provides great potential - regarding to the upcoming limitation of the
particle number with EURO 6.
Recommendation:
Ethanol blends between 15% and 25% (named E20/25 in this study) provide
interesting potential regarding exhaust emissions and efficiency increase.
However, no adequate studies on modern engines (EURO 6) for E20/25 with
respect to the full utilization of the theoretical potential of ethanol are available.
Further research is required, especially regarding the optimization of fuel
consumption and the emission of particles.
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Page 1
1 Motivation
The present work is Task 2 of the E20/E25 technical evaluation study under
agreement between the Commission of the European Union and the European
Standardization
Committee,
CEN
(ENER/C2/GA/449-2012/SI2.641582):
Meta-
analysis of E20/25 trial reports and associated data.
In order to assess whether the introduction of a new technology or a new energy
source has consistently positive effects, a prior meta-analysis can prove useful. On
the one hand, based on the available literature according to a comprehensive
literature search, the current state of knowledge can be summarized very clearly and
statistically processed. On the other hand, it reveals outstanding issues that need to
be further investigated in detail prior to the introduction of a new technology.
2 Meta-Analysis
2.1 Methodology
The analysis of the collected data is performed using a statistical analysis. As defined
in the contract a meta-analysis (1) can be performed. For this purpose, a systematic
approach has been carried out and the collected data is processed as follows.
The selection and filtering of the literature was performed according to the PRISMA
schema. Figure 2-1 illustrates the procedure for this method by means of flow chart.
2
Figure 2-1: PRISMA Flow Diagram (2)
On the basis of a comprehensive literature search, in the first step (Identification) 200
studies were found. Subsequently the duplicates were discarded and on the basis of
the abstracts a pre-selection was made. Approximately 100 studies were left after the
“screening” phase. In the "eligibility" phase, the remaining studies were worked
through in detail. On the basis of the boundary conditions and investigation priorities
contained in the studies about half of them were likewise sorted out. Finally, 50
studies were included in the meta-analysis. As is generally known, almost all vehicles
in Brazil are capable for ethanol-blends, but only a few studies have been included in
this study. This topic will be discussed in detail in chapter 4.3.
Each study recorded in this investigation proceeds to a record in the respective
category (emissions, fuel consumption, etc.). In studies, which contain more than one
result an average over all available values was built, so that for each study only one
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3
value is considered in the evaluation. Furthermore, each study was weighted by the
following criteria:

reputation of the study authors;

extent of the measurements; and

boundary conditions (e.g. base fuel, engine, mixture preparation, …)
The resulting data sets are averaged over the respective ethanol content and in
addition, the 90% confidence interval is evaluated. For clarity and because of the
focus of the work on an ethanol content between 15 and 25 percent, the results are
divided into the following ethanol-gasoline blend groups:

E0: no ethanol content in fuel

E5/10: ethanol content >0% and <15%

E20/25: ethanol content between 15% and 25%

E30/50/70: ethanol content >25% and <75%

E85: ethanol content between 75% and 99%

E100: 100% ethanol
Figure 2-1 shows the ethanol fractions of the respective studies, which were included
in the meta-analysis. The y-axis shows the reference number of the investigated
studies (see chapter 6.1). On the x-axis the different ethanol content of the individual
studies are shown. A point in the figure indicates that in the particular study (line) the
respective ethanol content (column) was examined. As can be seen from Figure 2-2
the data, included in the meta-analysis, in the range between 15 and 25 percent
ethanol have a very good density focused on E20.
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4
E0
E5/10
E20/25
E30/50/70
E85
E100
Figure 2-2: Investigated ethanol contents in the literature used for the meta-analysis.
To be able to compare the results from different studies it is necessary to normalize
the results. So the base fuel (E0) always is represented by 100% and the variance for
E0 is therefore always zero. In three literatures the base fuel was in the range of
E5/10. For this studies, the influence of the ethanol content on the engine efficiency
and emissions were based on the specific base fuel. To make the results comparable
with the results of the studies with E0 as base fuel an offset was added to the data.
The offset is obtained from the average value for the specific ethanol content of the
base fuel, which was determined by the studies with E0 as base fuel.
If the value of an ethanol-gasoline blend group decreases below 100%, the absolute
value is smaller than that of the comparative fuel (E0). If the value increases,
however, this means that the absolute value also increases.
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3 Basics for usage of alternative fuels in SI engines
This chapter serves as an introduction to the topic of alternative fuels for a better
understanding of the results of the meta-analysis without being a technical expert in
the field of internal combustion engines.
3.1 Increasing the efficiency by “Downsizing”
The increase in efficiency is an important step towards reducing fuel consumption.
Figure 3-1 show the effect of shifting the actual operating point (A) toward higher
loads and lower speeds (B) at the same power of 30kW. This so called downsizing is
achieved by an increase of the load especially at low speeds. Due to the reduction of
losses like the charge exchange losses, mechanical losses and the wall heat losses
a higher efficiency is achieved. This subsequently results in a lower specific fuel
consumption.
Figure 3-1: Characteristic fuel consumption map of a SI engine (3)
The downsizing concept as it is used today in many vehicles, has great potential for
reducing CO2 emissions. Downsizing and downspeeding are combined in order to
achieve the desired fuel savings. An increase in the mean effective pressure is for
such a fuel saving strategy essential (3) (4) (5). However, this increases the problem
of irregular combustion phenomena.
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Limits for downsizing
But this downsizing trend is limited by the high mean effective pressures and other
increasing demands which lead to numerous restrictions:

knocking

pre-ignition phenomena

higher thermal and mechanical load

CO2 emission limits

costs
A modern more fuel-efficient engine must meet the following requirements today (3)
(5) (6):

high torque resp. quick response, even at low speeds in the stationary and
dynamic operation

the optimization of the tendency to knock at high loads

high compression ratio (possible by direct injection)

optimized centre of combustion which leads to higher efficiency

reduced charge exchange losses even in the partial load range

reduction of the area with mixture enrichment, especially at high loads and
speeds according to component protection reasons
These requirements can only be achieved through the combination of different
technologies and strategies, such as gasoline direct injection, variable valve train,
supercharging, EGR, increasing the charge motion (swirl or tumble), and so on. As
gasoline direct injection has a direct influence on the usable potential of alternative
fuels, it is discussed in more detail below.
Gasoline Direct Injection (GDI)
By the gasoline direct injection the heat of vaporization of the fuel spray cools down
cylinder charge, whereby the temperature of the cylinder charge is reduced. Cooling
has also a positive effect on the knock- and pre-ignition tendency. Due to the cooling
of the cylinder charge a higher compression ratio can be achieved. Furthermore the
volumetric efficiency of the engine is also increased by the cooling of the cylinder
charge.
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7
In combination with variable valve trains substantial improvements in gas exchange
are possible. Thus, the direct gasoline injection in combination with a supercharged
downsizing engine is an essential part of modern gasoline engines (3) (5) (6).
3.2 Influence of Ethanol on RON (Knock-Resistance)
For fuel economy at part load modern gasoline engines have a high compression
ratio. This results in highly supercharged engine concepts in the full load to critical
conditions in the combustion chamber. Due to the propagating flame front a critical
state occurs in the further compressed end gas and leads at one or more locations to
self-ignition. The resulting very high pressure gradient (see Figure 3-3) spread in the
form of pressure waves in the sound speed range and can cause severe material
damage. Knocking combustion also produces a high thermal stress, which in turn can
be trigger so called glow-ignitions (see pre-ignition phenomena).
Measures to improve the knock resistance are:

more knock resistant fuels

sufficient cooling of the combustion chamber and the intake air

appropriate combustion chamber layout

retarding the ignition timing (thermal efficiency ↓)

reducing the boost pressure (thermal efficiency ↓)

reducing the compression ratio (thermal efficiency ↓)
The above measures to avoid the knock problem show that in many ways only
"trade-off" solutions can be found. Their optimization is a major challenge for engine
designers (3) (4) (5) (7) (8).
Through the use of ethanol, almost all the points mentioned above can be
positively influenced. As can be seen from Figure 3-2 the RON increases with
increasing ethanol content.
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Figure 3-2: Influence of Ethanol content on RON for splash blends for base fuel RON
98
This characteristic is valid for all splash blends, regardless of the base fuel (possible
country-specific differences in the base fuel - USA, Europe, China, Brazil must be
considered). In match blends, however, the RON is kept constant over the
proportioning rate. This is achieved by base fuels with lower RON.
Pre-ignition phenomenon
One of the main limits of downsizing engines are irregular combustion phenomena
that mainly occur at high pressure, high temperature and low speeds. In contrast to
knocking, the ignition of the mixture takes place before the combustion can be
initiated by the spark. Knocking combustion can be prevented by a retardation of the
ignition timing, whereas a pre-ignition is only partially influenced by the ignition
timing. In Figure 3-3, the difference of a normal- and a knocking combustion as well
as a pre-ignition are illustrated by their cylinder pressure curves.
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Figure 3-3: Cylinder pressure curves of a normal- and a knocking combustion as well
as a pre-ignition (9)
Since pre-ignitions lead to a significant increase of the cylinder pressure (up to
250bar) often severe engine damage will occur. For this reason, the following preignition causes must be avoided by appropriate measures:

oil droplets and deposits (partially avoidable through crankcase ventilation and
a good oil separator)

"Hot spots" (critical hot spots, such as the spark plug can be constructively
reduced)

chemical reaction kinetics (e.g. radicals caused by high EGR-rates resp. hot
residual gas can be avoided by appropriate valve timing) (5) (9)
Thermal and mechanical load
Increased thermal stress on the components that are in direct contact with the hot
combustion gases, is also a result of high mean effective pressures, as it is the case
for downsizing engines. Primarily, these are the cylinder head, piston and cylinder
liner. Enhanced cooling measures are therefore an integral part of such concepts.
The necessary of retarding the ignition timing by the knock control system causes an
increased thermal load of the exhaust components. Exhaust valves, turbocharger
and three-way catalyst must therefore be adequately protected. Although a mixture
enrichment protects exhaust valves, turbocharger and three-way catalyst from
thermal overload, but leads to an increase in fuel consumption, as well as to
increased CO and HC emissions. The cooling effect of the cylinder charge by
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using ethanol, as explained before, has a positive effect on above-mentioned
problems (4) (5).
3.3 Alternative fuels for gasoline engines
Generally, there are several alternatives for the use of alternative fuels in
conventional SI engines. Taking into account the engine characteristics, sustainability
of fuels and the production expenses/ production facilities the following fuel
components have great future potential.

methanol (one C-atom)

ethanol (two C-atoms)

ethanol with a water content of 7 vol%

1-propanol (three C-atoms)

1-butanol (four C-atoms)
In Figure 3-4 the relevant properties of the substances listed above are shown.
Figure 3-4: Properties of different alcohols (10)
The listed fuel properties have a significant influence on the combustion process.
Here especially the higher heat of vaporization of alcohol fuels in contrast to regular
gasoline should be mentioned, which result in increased cooling of the cylinder
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charge. The higher heat of vaporization of alcohol fuels leads to a number of positive
effects on the combustion process.
Improved cooling of the mixture, among other things leads to a higher cylinder filling,
and results in an increase of engine torque. This effect can be utilized much better in
DISI engines than PFI engines. Strong wall wetting with fuel (due to high boiling
points of the alternative fuels) ensure in PFI engines that the heat required for
evaporation is partially removed from the intake manifold. In the homogeneous DISI
engines the heat for evaporization is mainly removed from the cylinder charge. The
cooling and, consequently, an advanced combustion position (MFB50% - defines the
centre of combustion - is closer to the TDC) also provide a lower exhaust gas
temperature.
The usually, at higher loads required enrichment (λ <1), to protect engine
components, thus largely unnecessary. The normally required mixture enrichment at
higher loads for component protection is for this reason largely unnecessary. A
further advantage is the mitigation of knocking (undesirable combustion phenomena
which can damage the engine). Especially in the knock-limited full load operation of
the engine ethanol allows compared to regular gasoline a more efficient location of
the centre of combustion.
An optimal centre of combustion not only leads to better efficiency, but also to a
higher torque as is required for efficient downsizing engines. Further the use of
ethanol allows an increase of the compression ratio due to the mitigation of the knock
problem and thus lead to a further improvement of the thermal efficiency. Also, the
lower the C-atom number and the higher the mass-based oxygen content of alcohols,
the shorter the burning duration and the ignition delay (shown in Figure 3-5), since
the higher the oxygen content increases the reactivity.
In Figure 3-5, different engine operating parameters are shown during a boost
pressure variation. In Figure 3-5 a regular gasoline (E5 RON95) and two splash
blends E20 and E85 are compared. The benefits of ethanol are clearly visible. With
E85, the most optimal centre of combustion (MBF50%) can be achieved without any
knock phenomena. The CoV value characterizes the engine running smoothness.
Due to the most optimal centre of combustion E85 also shows the lowest CoV level.
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The short ignition delay time and the fastest burning duration is explained in the
higher reactivity of ethanol caused by the high content of oxygen. The importance of
richer air-fuel-ratio to reduce thermal load, as seen in Figure 3-4, is not necessary
with ethanol because of the cooling effect. The retardation of the ignition timing was
only necessary on the basis of peak pressure limit (see PMAX-diagram in Figure
3-5). Accordingly, with E85 the highest indicated mean effective pressure and peak
pressure can be achieved.
Figure 3-5: Engine parameters for different fuels at 2000rpm, WOT (5)
Alcohols with a lower number of carbon atoms, such as ethanol, have a lower
stoichiometric air-to-fuel ratio, and a lower heating value. Due to the lower
stoichiometric air-to-fuel ratio, more fuel must be introduced into the cylinder at the
same air mass. The resulting additional cooling effect (more fuel to be evaporated)
amplify above aspects, the disadvantage of the lower heating value (higher
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gravimetric and volumetric fuel consumption for the same energy content) remains,
however. The higher boiling temperature and the lower vapour pressure of ethanol
are responsible for their poor cold-start performance. At higher ethanol blend rates
such as E85 the boiling temperature is, for example, higher than the beginning of the
boiling range of regular gasoline.
Influence on the efficiency
Almost all the above factors lead to an increase in efficiency. A cooler combustion
process has lower wall heat losses. Also the enrichment requirement (λ <1) at high
temperatures thereby largely mitigated, which leads to a reduced fuel consumption
and emissions advantages. Due to the higher knock resistance with appropriate
engine application and a more optimal centre of combustion further efficiency
benefits can be achieved. A shorter combustion duration and a more efficient
combustion, as in the case of ethanol, also give an increase in the efficiency (5) (10)
(11) (12) (13)
Influence on the pre-ignition tendency
The use of ethanol as a mixing component for regular gasoline (E5 RON95) lead to a
significant decrease in pre-ignition frequency as described in (14). Depending on the
different blend rates pre-ignitions can significantly be reduced. With E85 the best
results were achieved. In (15) oxygenates, such as ethanol, are described to have a
high resistance against pre-ignitions, assuming an ignition in the gas phase.
Considering an ignition on hot surfaces so-called "hot spots" a decrease in the preignition resistance with increasing ethanol content is observed in (16). A direct
comparison between a DISI- and a MPI-engine during a boost pressure variation
shows generally a higher pre-ignition frequency with external mixture formation. Due
to admixing of ethanol a higher intake manifold pressure is reached in both cases.
But only the DISI engine can utilize the full potential of ethanol, which is clearly
evidenced by a very low pre-ignition frequency at high ethanol content and internal
mixture formation (see Figure 3-6) (5) (17).
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Figure 3-6: Pre-ignition frequency of the tested fuels during a boost pressure
variation for a DISI- and a MPI-engine (17)
Cold start behaviour of ethanol
One reason for the poor cold-start performance of E100 is that as single component
fuel it has a fixed boiling point of 78°C and thus the volatile components as in regular
gasoline are missing. Another reason is the high heat of vaporization, which is
responsible for additional cooling of the mixture (18). In Figure 3-7 the different
boiling temperatures and heat of vaporizations are plotted for gasoline and alcohols.
Figure 3-7: Difference of evaporation properties of different fuels (18)
However, this study focused on ethanol blending rates E20/25, thus no cold
start problems are expected.
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4 Results from the meta-analysis
The results of the evaluation of the meta-analysis are presented in this chapter and
will be discussed in detail. The results are based on the literature listed in Chapter
7.1. The effects of ethanol blends were examined for the following properties:

Fuel Consumption and Energy Efficiency (Chapter 4.1)

Carbon dioxide emissions (CO2) (Chapter 4.2)

Carbon monoxide emissions (CO) (Chapter 4.2.2)

Hydrocarbon emissions (HC) (Chapter Error! Reference source not found.)

Nitrogen oxides emissions (NOx) (Chapter 4.2.4)

Particle emissions (Particle) (Chapter 4.2.5)
To enhance the readability and clarity of the study the individual analysed groups are
divided always according to the same sequence. First, a brief understandable
introduction to each topic, followed by the results of the present meta-analysis and
the discussion of the results.
4.1 Fuel Consumption and Energy-Efficiency
Fuel Consumption and Energy Efficiency are one of the most important factors, when
evaluating an alternative fuel for gasoline. Beside the Fuel properties it is of peculiar
interest if there exist fundamental advantages and disadvantages.
Specific Fuel Consumption (SFC)
For a better understanding of the influencing variables of ethanol on the fuel
consumption different aspects of the fuels must be considered. Generally, there are
several possible alternative fuels for use in conventional SI Engine (see Chapter 3.3).
Table 4-1 shows the differences in the fuel properties between regular unleaded
gasoline and pure ethanol (19) (20) (21) (22).
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Gasoline
Ethanol
≈C5-C12
C2H6O
43.5
26.8
32
21.1
≈350
920
Reid Vapour Pressure b) [kPa]
61
15.5
Stoichiometric air/fuel-ratio [-]
14.6
9
720-775
794
Oxygen [%w]
2.7
34.7
Auto ignition temperature [°C]
257
425
Laminar flame speed c) [cm/s]
≈33
≈39
27-225
78
0
100
27.6
0
Research Octane Number RON [-]
95
109
Motor Octane Number MON [-]
85
90
Chemical formula
Low Heating Value [MJ/kg]
Low Heating Value [MJ/l]
Latent heat of vaporization a) [kJ/kg]
Density [kg/m3]
Boiling Point [°C]
Water solubility [%]
Aromatics volume [%]
Table 4-1: Fuel properties of unleaded regular gasoline and ethanol [3, 23, 28, 36]
a) at 25°C
b) at 37.8°C
c) laminar flame speed at 100kPa and 325°C
In particular, the following properties

Low heating value (leads to increased fuel consumption)

Latent heat of vaporization (influences knocking, enables aggressive
downsizing)

Reid vapour pressure (influences the cold-start performance)

Water solubility (due to the hygroscopic behaviour of ethanol phase separation
may happen when in contact with water)
have a strong impact on the key aspects of engine operation with pure ethanol resp.
ethanol-gasoline blends. As seen before ethanol has a lower heating value as
gasoline. That means, that one litre respectively one kilogram ethanol contains less
energy than the same amount of gasoline. To assess how much fuel an internal
combustion engine on the engine test bench consume we often use a so called
specific fuel consumption (SFC). The SFC gives the volumetric or gravimetric fuel
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consumption based on the generated engine power. Equation 4-1 shows the
relationship between fuel consumption and the generated engine power.
𝑆𝐹𝐶 [
𝑘𝑔
𝑙
𝑚̇𝐵
𝑜𝑟
]=
𝑘𝑊ℎ
𝑘𝑊ℎ
𝑃
Equation 4-1
Figure 4-1 shows the results from the meta-analysis for the specific fuel consumption.
Figure 4-1: Specific fuel consumption
It turns out, as seen in Figure 4-1, that the SFC is rising consistent with increasing
amount of ethanol in the fuel-blend, as mentioned before. Especially for E20/25 the
meta-analysis show an increase by 3% in average.
Taking into account the lower heating value of ethanol, there results the image
shown in Figure 4-2.
Theoretically, the fuel consumption when using E20/25 would rise by approximately
8%. The results from the meta-analysis, however, show only an increased
consumption of about 3%, which reflects the increased thermodynamic efficiency due
to the use of ethanol. These results are consistent with the data extracted from the
meta-analysis for the engine efficiency.
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Figure 4-2: Theoretical fuel consumption due to the lower heating value of ethanol
compared to the fuel consumption resulting from the meta-analysis
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4.2 Emissions
In this study a distinction is made between the raw emissions (engine-out) and the
end-of-pipe (tailpipe) emissions. The principal effect of ethanol blends on exhaust
emissions can be significantly better illustrated using the engine-out emissions. In a
real vehicle operation, the end-of-pipe emission of more importance as long as the
exhaust aftertreatment system (3-way catalyst) is working properly.
In order to give in the following sections a better overview of the results of the
emission results, the ideal chemical reaction equations for a particular gasoline
model fuel (Equation 4-2) and ethanol (Equation 4-3) are compared [9].
𝐶7 𝐻13.3 + 10.33(𝑂2 + 3.785𝑁2 ) = 7𝐶𝑂2 + 6.66𝐻2 𝑂 + 39.1𝑁2 + 4.19𝑀𝐽
Equation 4-2
3.44𝐶2 𝐻6 𝑂 + 10.33(𝑂2 + 3.785𝑁2 ) = 6.88𝐶𝑂2 + 10.32𝐻2 𝑂 + 39.1𝑁2 + 4.24𝑀𝐽
Equation 4-3
According to the Equation 4-2 and Equation 4-3 it can be seen that ethanol has
approximately 30% more triatomic molecules in exhaust gas than gasoline. The
result is a higher specific heat capacity and therefore lower exhaust gas
temperatures, lower wall heat losses and consequently a higher thermal efficiency
[9]. This effect is further enhanced by the significantly higher latent heat of
vaporization. In the real combustion, however, incur additional components, which
results from incomplete combustion, for example. Among others the limited pollutants
CO, HC, NOx and particles.
The exhaust aftertreatment system, for the SI engine, a 3-way catalyst has the task
of reducing undesirable combustion products (limited pollutant emissions) and
convert them into harmless components. The CO and HC are oxidized and the NOx
emissions are reduced, as shown in Equation 4-4, Equation 4-5 and Equation 4-6.
2 𝐶𝑂 + 𝑂2 → 2 𝐶𝑂2
𝑛
𝑛
𝐶𝑚 𝐻𝑛 + (𝑚 + ) 𝑂2 → 𝑚 𝐶𝑂2 + 𝐻2 𝑂
4
2
Equation 4-4
2 𝑁𝑂 + 2 𝐶𝑂 → 𝑁2 + 2 𝐶𝑂2
Equation 4-6
Equation 4-5
As shown in Figure 4-3 this conversions only work in a small Air/Fuel-Ratio window
near the stoichiometric Air/fuel-Ratio.
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The more important the property of ethanol is to keep the enrichment requirement as
low as possible in the full load, as already explained above. Thus, the three-way
catalyst can fulfil its function over a wider operating range, compared to E0.
λ-range
Figure 4-3: Schematic influence of the Air/Fuel-Ratio on the conversion level of the 3way-catalyst (8)
4.2.1 CO2 emissions
Carbon dioxide does not primarily belong to limited emissions, but is a final product of
ideal combustion. Therefore, the CO2 levels in exhaust gas give a measure of
efficiency for the combustion.
Figure 4-4 shows the influence of different ethanol blends on the CO2 emissions,
which were evaluated for the meta-analysis. As Equation 4-7 shows, the CO2
emissions in figure 4-4 are referred to the engine performance.
[𝐶𝑂2 ] =
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𝑘𝑔
𝑘𝑊ℎ
Equation 4-7
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Figure 4-4: Engine-out CO2 emissions
In the range between E0 and E50, the CO2 emissions tend to rise. This is a sign of
an improved combustion, especially in combination with reduced CO emissions (see
Chapter 4.2.2). The decrease in CO2 emissions above E50 does not mean that there
is incomplete combustion again. There the favourable H/C ratio of ethanol comes into
play and therefore more H2O than CO2 is formed.
The end-of-pipe CO2 emissions, see Figure 4-5, also decrease at low ethanol
content, as the conversion of CO and HC to CO2 takes place in the catalyst. As has
been shown earlier the efficiency of the catalyst also increases with increasing
ethanol content. Apart from this, the catalyst can be operated in a wider range
without full load enrichment (lambda=1) with increasing ethanol content. Since
generally the CO- and HC emissions decrease in this area therefore CO 2 emissions
are even lower after the catalyst.
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Figure 4-5: End-of-pipe CO2 emissions
As can be seen from the meta-analysis results the CO2 end-of-pipe emissions after
complete combustion drop by approximately 5% for E100 compared to E0. This is
consistent with the theoretical reduction of CO2 emissions through the better C/H
ratio of ethanol, as shown in Equation 4-2 and Equation 4-3.
4.2.2 CO emissions
Carbon monoxide results by combustion of fuel under oxygen deficient, if the carbon
cannot be burnt completely. A full oxidation to CO2 is only possible with sufficient
oxygen. That means that the CO concentration in the exhaust gas increases with
decreasing λ, as is the case for fuel enrichment (see Figure 4-6). (8).
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Figure 4-6: Pollutant formation as function of the air/fuel ratio (8)
Figure 4-7 shows the result from the meta-analysis for the engine-out CO emissions.
Figure 4-7: Engine-out CO emissions
Figure 4-7 shows a clear reduction in CO emissions with increasing ethanol
concentration in blend. Especially for E20/25 the CO emissions can be reduced by
approximately 10% in average. On one hand the need for fuel enrichment in a wide
range of operating is unnecessary, which results in lower CO emissions due the
combustion process, as previously mentioned. On the other hand fossil fuel (E0)
contains about 30% more carbon than ethanol, which in turn can lead to a higher
percentage of unburned carbon. At the same amount of air and Lambda this effect is
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almost equalized, due to the higher amount of fuel required at higher ethanol content.
The faster and more complete combustion of ethanol, according to the higher oxygen
content (see Figure 3-4), leads to a reduction of the unburned carbon.
As can be seen from Figure 4-8 the CO end-of-pipe emissions also can be reduced
by increasing ethanol content in blend. The need for enrichment with E0 has an even
greater importance here, because the three-way catalyst ensures only in a very
narrow lambda window high conversion rates (see Chapter 4.2). If the motor can be
operated stoichiometrically in a larger map range, as is possible with ethanol, the CO
emissions can be reduced further because of the higher conversion rate of the 3way-catalyst. Compared with Figure 4-7 the difference between E0 and E20/25 is
quite more apparent and the advantage of ethanol is even better obvious.
Figure 4-8: End-of-pipe CO emissions
4.2.3 HC emissions
HC emissions are unburned hydrocarbons. These occur during the combustion
process mainly from lack of oxygen and cool local temperatures. Origin of HC’s are a
rich engine operation (λ<1) and formation of wall film, similar to the origin of the CO
emissions. Wall film is the agglomeration of fluid fuel on components like the cylinder
liner, the piston, and the cylinder head. At this places the flame front cools down so
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heavily, that the fuel cannot burn completely. Figure 4-9 shows the result for the
engine-out HC emissions.
Figure 4-9: Result of the meta-analysis for the engine-out HC emissions
As it turns out the HC engine-out emissions decrease on average over the
investigated studies with increasing ethanol content. For E20/25 the HC emissions
decrease in general by approximately 10%. However, it should be noted that from an
ethanol content of over 75% the standard deviation increases greatly. This is a result
of reinforced wall film formation. This can be counteracted by a suitable motor
application and an injector optimized for the use with ethanol. The generally
recognizable reduction of HC raw-emissions is caused by the leaning effect due to
the ethanol addition and significantly less high-boiling fuel components in the fuel.
This in consequence means that the aromatic content decreases in the fuel. This
high-boiling fractions are possibly responsible for wall film formation and would lead
to significantly higher HC emissions, as seen by E0.
The results for HC emissions after the aftertreatment system show a more
ambiguous picture, as shown in Figure 4-10.
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Figure 4-10: Result of the meta-analysis for the end-of-pipe HC emissions
Here also the tendency of decreasing HC emissions with increasing ethanol content
is obvious. Especially for E20/25 the HC emissions decrease slightly by
approximately 4% in average. It should be noted, that the large 90% confidence
interval indicates, that the results depend strongly on the engine application.
4.2.4 NOx emissions
The term nitrogen oxides NOx stands for a plurality of nitrogen-oxygen compounds
(NO, NO2, N2O, ...). Only the two representatives NO and NO2 are produced in
gasoline engines in larger quantities. Nitrogen oxides are jointly responsible for
climate change. Especially NO2 is directly harmful to humans. In addition, NO2 reacts
under UV radiation to ground-level ozone (O3), which is for the people, even in small
quantities an irritant gas (23).
Two mechanisms are mainly responsible for the NOx formation during the
combustion (24):

Zeldovich mechanism

Fenimore mechanism
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In this context, the NOx formation from fuel-bound nitrogen should be mentioned. In
relation to the Zeldovich mechanism, illustrated in more detail below, the resulting
amounts of NO are, however, negligible.
The Zeldovich mechanism is due to its high activation energy of 319 kJ/mol for the
initiation reaction, extremely temperature dependent. The decisive factor is the
availability of atomic oxygen, which is formed in internal combustion engines only at
very high temperatures (>1600K). Due to the high temperatures required to initiate
the Zeldovich mechanism it is also referred to as thermal NO formation (25).
Figure 4-11 shows the results from the meta-analysis for the NOx engine-out
emissions.
Figure 4-11: Engine-out NOx emissions
As it turns out the NOx emissions rise at first, before they start to decrease at an
ethanol content of about 50%. Finally the NOx emissions decrease below the value of
E0. As already mentioned before a shorter burning duration in turn leads to an
increased cylinder temperature and hence an increase in NOx emissions. The cooling
effect of alternative fuels can compensate this increased cylinder temperature above
a certain blend ratio, and only then, alcohol fuels lead to reduced NO x emissions. The
bounded oxygen content in ethanol leads to a more homogeneous temperature
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distribution which amplifies this effect. Especially for E20/25 the NOx emissions
increase approximately by 20% in average.
Similar to the engine-out NOx emissions the emissions after the aftertreatment
system increase with low ethanol content and begin to decrease with an ethanol
content greater than E20/25 continuously, see Figure 4-12.
Figure 4-12: End-of-Pipe NOx emissions
It’s important to know, that because of the effective three-way catalyst system
(conversion rate > 90%) the absolute level of the NOx end-of-pipe emissions is very
low. (in most cases < 100 ppm)
4.2.5 Particle emissions
The particulate emission of homogeneous operated gasoline engines is caused by
an imperfection of mixture formation (26), which more clearly affects the directinjection gasoline engine as PFI gasoline engine.
Due to the lower mixture formation time between the end of injection and the start of
ignition locally very rich zones may be present, mainly fuel-wall interaction, which
represent particle sources in the homogeneous spark-ignition engine. If there is not
enough time for complete evaporation of the wall film, this burns in a highly sooting
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diffusion flame. Due to lack of oxygen, there are hardly any oxidation reactions of the
formed soot (27).
Favourable conditions for particle formation are a locally rich combustion at locally
high temperatures in the range of 1700 to 2600K (28). Figure 4-13 gives a schematic
view of particle relevant physical sources.
Figure 4-13: Schematic view of particle relevant physical sources (28)
The main in-cylinder particle sources are (28):

piston wetting,

liner wetting,

combustion chamber roof wetting,

interaction with intake valve,

injector deposits (tip sooting) and

inhomogeneity and diffusion flames
Particle emissions are strongly related to the aromatics components, which are
boiling at high temperatures. Due to blending of high proportions of ethanol the
aromatic components are decreased, which subsequently decreases soot precursors
(29), (30). Further, the oxygen in ethanol results in more favourable local conditions
and thus acts against the formation of particles (31).
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It should be noted that currently only a small number of studies exist that deal with
particle emissions in SI engines. The results of the meta-analysis are shown in Figure
4-14.
Figure 4-14: PM-Emissions
The engine-out emission in case of the particle emission are also representative for
the tailpipe emissions, because today's gasoline vehicles have no particle filter,
which is the only way to minimize particle emissions in the exhaust system.
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The results of the meta-analysis for the particle number are shown in Figure 4-15.
Figure 4-15: PN-Emissions
The reason for the increased particulate emissions (PM and PN), in spite of the
theoretical trend of lower particulate emissions with increased ethanol content is as
follows. The discussed engines in this analysis are all direct injection engines, since
MPI engines hardly form particle emissions. The increase in particulate emissions is
due to increased wall- and piston crown wetting of the direct-injection engines, if they
are operated with high ethanol content.
Basically, it can be said that an engine which was not calibrated before for high
ethanol blends can not use the more favourable properties of ethanol. In that case an
increase in the particle emissions, as shown in Figure 4-15 is the consequence.
Direct-injected gasoline engines have a high potential for increasing the efficiency but
they emit due to internal mixture formation a higher level of particulate emissions
than PFI-engines (31). As shown by recent works, by proper application of the ECU
the particle emissions can be drastically reduced as can be seen in Figure 4-16.
Figure 4-16 shows the cumulated particle number [1/km] during the NEDC for a DISI
engine at different ethanol-gasoline blends.
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Figure 4-16: Reduction of the particle number during the NEDC in dependence of the
ethanol content (31)
As can be seen from the study results shown in Figure 4-16 the particle-emissions
can be reduced by approximately 50% for E20 by proper application of the ECU.
4.2.6 Efficiency
The thermal efficiency, see Equation 4-8, of an engine is known as the relationship
between the power the engine can generate (E OUT) considering the energy content in
the fuel (EIN).
𝜂𝑡ℎ =
𝐸𝑜𝑢𝑡
𝐸𝑖𝑛
Equation 4-8
Figure 4-17 shows the influence of different ethanol blends on the engine efficiency,
which were evaluated for the meta-analysis.
As already shown above the engine efficiency can be increased by admixing ethanol
in the fuel combined with appropriate measures. Especially for E20/25 the efficiency
increases by 5% in average. Figure 4-17 shows that the 90% confidence interval
reach in all areas under the 100% line. This expresses that there have been no
adjustments of the engines to use the advantages of increased ethanol content in the
fuel.
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Figure 4-17: Engine efficiency
4.3 Brazil
The vehicles used in Brazil are mostly specially adapted to the climatic conditions
and fuel properties in Brazil. These adjustments are mainly on the application level.
This means that the engine hardware only is capable for ethanol, the engine
electronic control algorithms are matched to the ethanol content. On the other hand
this means, that those cars are not optimized for E20/25.In particular, in Brazil, the
cold start behaviour, due to the higher average temperatures and lower customer
claim, does not play a role as important as in Europe.
The basic physical relationships and properties of ethanol, when used in the internal
combustion engine, were consistently confirmed by the meta-analysis, as shown
above. These results are therefore in general and hence valid worldwide and can not
be restricted to certain countries.
Although almost all vehicles in Brazil are capable for ethanol, only a few literatures
from Brazil were identified in the identification phase (see chapter 2.1). During the
“screening” and the “eligibility” phase this studies were sorted out, since in most
literatures the relation to ethanol contents less E20/25 is missing.
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5 Conclusion and further topics to be investigated
It has been proven that with increasing ethanol content the efficiency of the engine
increases. However, for single studies the efficiency decreases, which indicates that
there have been no adjustments to the engines to use the advantages of increased
ethanol content in the fuel.
Therefore the energy related fuel consumption decreases despite a higher volumetric
fuel consumption. Based on the volumetric fuel consumption, for low contents of
ethanol (E5/10) there is a small (1% to 2%) statistically significant difference to E0,
where as the use of E20/25 results in an increase by about 3% in average.
The main findings from the meta-analysis for the emissions are:

The CO2 end-of-pipe emissions decrease by about 5% for E100 in average.
For E20/25 there is still a benefit by about 2% in average compared to E0.

Generally the CO engine-out emissions decrease by up to 10% for E20/25 in
average and by up to 20% for the end-of-pipe emissions. However, in
individual cases, CO emissions also increase, especially at higher mixing
rates. This is due to a lack of adaptation of the operating strategies of the
increased ethanol content. This results in increased wall wetting with fuel.

The HC engine-out emissions are also reduced by about 10% for E20/25 in
average. But in some cases HC emissions increase for the same reasons as
previously discussed for the CO emission. The HC end-of-pipe emissions
decrease by about 5% for E20/25 in average.

The NOx engine-out emissions increase for E20/25 by 20% in general. The
reasons are higher peak temperatures in the cylinder during the combustion.
Because of the good conversion rate of the 3-way catalyst, the NOx end-ofpipe emissions drop to the level of E0.

The Particle-Emissions have to be investigated further. In general there is the
ability to decrease the particle-emissions with E20/25. But it is essential to
optimize the engine for higher Ethanol-contents.
Identified gaps
Certainly it cannot be assumed that every vehicle reacts in the same way on the
addition of ethanol. As the study reveals, there are also cases where the emissions
increase and the efficiency decrease, although according to the general trend it is not
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likely. The vehicles must be adapted to the higher ethanol blends, especially in terms
of cold-start behaviour and particulate emissions for direct injection gasoline engines.
In particular, the impact on particulate emissions have shown that in this area are
further investigations necessary to be able to transfer the basic correlation into the
real engine operation.
It is essential to optimize the vehicles for higher ethanol contents. Therefore it´s
necessary to adapt the engine control unit (calibration), the mixture preparation and
operating strategies.
Introducing higher ethanol blends without adapting the vehicles would amongst
others lead to a small but increased volumetric fuel consumption since the energy
content of ethanol is lower than for pure gasoline. In addition, ethanol affects certain
plastic compounds and sealing elements and therefore a suitable material should be
chosen.
Therefore, the proposed solution explained in „Terms of References for Metaanalysis for an E20/25 technical development study Task 2: Meta-analysis of E20/25
trial reports and associated data“ can be supported from a technical point of view.
The solution proposes the following three-step process:
1. First, that E20/25 capable cars are brought to market;
2. Second, once a sufficient number of these cars is available, E20/25 fuel will be
introduced;
3. Third, once the fuel is in place, the auto industry would commercialize E20/25
optimized cars.
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6 Annex
Numerical data for Figure 4-1: Specific fuel consumption:
SFC
E0
E5/10
E20/25
E30/50/70
E85
E100
100,0%
101,1%
103,1%
111,0%
125,2%
140,3%
Numerical data for Figure 4-2: Theoretical fuel consumption due to the lower heating
value of ethanol compared to the fuel consumption resulting from the meta-analysis:
E0
E5/10
E20/25
THEORETICAL FC
100,0%
102,9%
107,7%
FC
100,0%
101,1%
103,1%
Numerical data for Figure 4-5: End-of-pipe CO2 emissions:
CO2
E0
E5/10
E20/25
E30/50/70
E85
E100
100,0%
99,1%
98,3%
98,2%
95,1%
94,4%
Numerical data for Figure 4-17: Engine efficiency:
EFF.
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E0
E5/10
E20/25
E30/50/70
E85
E100
100,0%
101,8%
105,0%
105,9%
106,2%
109,1%
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7 Literature
In the following Section 7.1 the various references that were used to develop the
meta-analysis are listed in detail. In addition to the authors/titles the correspondent
country, the boundary conditions, the fuels, the study focuses and an evaluation of
the literature (0-1) are mentioned. Section 7.2 lists those references which were used
for further evaluation of the use of ethanol, especially in the areas of cold start,
downsizing and elastomer compatibility.
7.1 Literature for the meta-analysis
The literature listed here is not referenced in the text. It’s the literature that is included
in the meta-analysis. If a literature is used for the meta-analysis and is referenced in
the text the literature is listed in chapter 7.2 too.
[001.] Blassnegger, J., Knauer, M., Urbanek, M., et. al.; Endbericht zum Projekt
BioE: „Untersuchung: Emissionen bei der motorischen Verbrennung von
Biokraftstoffen
und
Kraftstoffmischungen“,
Institut
Verbrennungskraftmaschinen und Thermodynamik, Graz, 2009
Country:
Europe / Austria
Boundary conditions:
Chassis Dynamometer (NEDC, CADC (urban, road, motorway), const. load point)
Gasoline (DIN EN 228, RON 95, E00)
Ethanol: E3, E5, E10, E85, E75 (winter operation) with Ethanol according to DIN
15376
Test vehicle/engine:
EURO 4 passenger car calibrated to operate as flex-fuel
Engine: Inline-4, PFI, Turbo, engine displacement 1984cm3, 110kW @5100rpm,
TWC
Studies:
CO2, CO, HC, NOx, PM, PN, particle size distribution, PAH, Nitro PAH, Carbonyls,
mutagenicity, all “End of Pipe”
Loading:
0,9
[002.] Mahmoud K. Yassine, Morgan La Pan: Impact of Ethanol Fuels on Regulated
Tailpipe Emissions, Chrysler Group LLC, SAE International 2012-01-0872
Country:
North America / USA
Boundary conditions:
Chassis Dynamometer (75FTP)
Gasoline E0/Tier II EPA certification fuel
Ethanol: E10, E20, E85 splash blends with certification fuel E0, 3x E85 with different
RVP
Test vehicle/engine:
BIN 5 passenger car calibrated to operate as flex-fuel
Engine: V6, Port Fuel Injection, NA, engine displacement 3300cm3, vehicle mass:
4500lbs TWC
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Studies:
CO2, CO, HC (THC, NMHC, NONMHC, NMOG), NOx, Carbonyls
all “End of Pipe” at the three ambient temperatures under which emission certification
testing is required in the US for EPA and CARB
Loading:
0,9
[003.] Broustail G., Halter F., Seers P., Moreac G., Mounaim-Rouselle C.:
Comparison of regulated and non-regulated pollutants with iso-octane/butanol
and iso-octane/ethanol blends in a port-fuel injection Spark-Ignition engine,
Elsevier – Fuel 94 (2012) 251-261
Country:
North America / Canada, Europe / France
Boundary conditions:
Single cylinder engine test bench (two operating points: stoichiometric, lean)
Iso-octane as reference fuel.
Ethanol: E25, E50, E75, E100 splash blends with Iso-octane
Test vehicle/engine:
Single cylinder, PFI, NA, 4V, displacement 499cm3, CR=9.5; oil- and coolant
temperature constant at 80°C, intake air temperature at 23°C
Studies:
ISFC, CO2, CO, THC, NOx, Carbonyle, C2H2, C6H6
In addition, a reactor model (PSR...Perfectly Stirred Reactor (Chemkin package) only pure substances) was used to verify the measurement results.
Loading:
0,9
[004.] Chen L., Braisher M., Crossley A., Stone R., Richardson D.: The Influence of
Ethanol Blends on Particulate Matter Emissions from Gasoline Direct Injection
Engines, University of Oxford and Jaguar Cars, SAE International 2010-010793
Country:
Europe / United Kingdom
Boundary conditions:
Two engine test benches (one operating point: rich, stoichiometric, lean)
Two base fuels:
65%-Iso-octane / 35% Toluene as base fuel for the single cyliner engine
PURA (Unleaded Gasoline) from Shell for the V8-engine
Ethanol: E10 splash blend each with both base fuels
Test vehicle/engine:
Single cylinder: DI, NA, 4V, displacement 562cm3, CR=11.1; optical access
V8-engine: DI, NA, 4V, displacement 4999cm3, CR=11.5; EU4
Studies:
PM, PN, particle size distribution (pre- and post TWC)
Loading:
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[005.] Catapano F., Di Iorio S., Lazzaro M., Sementa P., Vaglieco B. M.:
Characterization of Ethanol Blends Combustion Processes and Soot
Formation in a GDI Optical Engine, Istituto Motori CNR, SAE International
2013-01-1316
Country:
Europe / Italy
May 2014
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Boundary conditions:
Optical single cylinder engine test bench (two operating points: 2000rpm WOT,
4000rpm partial load – stoichiometric)
Commercial European gasoline and bio-ethanol produced by Grape Pomace.
Ethanol: E20, E50, E85, E100 splash blends with commercial gasoline
Test vehicle/engine:
Single optical cylinder, DI, NA, 4V, displacement 250cm3, CR=10.5; 16kW
@8000rpm, 20Nm @5500rpm
Studies:
PM, PN (in accumulation and nuclei mode), particle size distribution, opacity, HC,
NOx, median diameter of the particle (in accumulation and nuclei mode)
Loading:
0,5 (optical single cylinder engine)
[006.] Li-Wei Jia, Mei-Qing Shen, Jun Wang, Man-Qun Lin: Influence of ethanolgasoline blended fuel on emission characteristics from a four-stroke
motorcycle engine, Elsevier – Journal of Hazardous Material A123 (2005) 2934
Country:
Asia / China
Boundary conditions:
Chassis Dynamometer (ECE15), five steady-state modes
Unleaded gasoline E0 base fuel produced by China National Petroleum Corp
Ethanol: E10 splash blend with base fuel
Test vehicle/engine:
HONDA CG125, Monocylinder, four-stroke, air-cooled, displacement 124cm3,
CR=9.0, 7kW @8000rpm
Studies:
HC, CO, NOx
Loading:
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[007.] Dedl P., Hofmann P., Geringer B.: Biobenzin aus Bioraffinerien – Eignung und
Potenzial von Alkoholen, Ethern, Furanen, BTL-Benzinen etc. Als
Benzinkomponenten, Institut für fahrzeugantriebe und Automobiltechnik TU
Wien, Wien, 2011
Country:
Europa / Austria
Boundary conditions:
Two Engine test bench
Chassis Dynamometer NEDC, CADC (urban, road, motorway)
Base Fuel: super gasoline EN228 with 10.0 %V ETBE
Blend Fuel: Ethanol E10, E25, E50
Test vehicle/engine:
Single cylinder engine: SI, PFI, 4V, displacement 341cm3, CR=12.1;
four cylinder engine & Test vehicle (FlexFuel): SI, DI, Turbo, 4V, displacement
1396cm3, CR=10.0, 125kW;
Studies:
HC, NOx, Efficiency, CO, CO2, FC
Loading:
0,9
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[008.] Turner D., Xu H., Cracknell R.F., Natarajan V., Chen X.: Combustion
performance of bio-ethanol of various blend ratios in a gasoline direct injection
engine, Elsevier – Fuel 90 (2011) 1999-2006
Country:
North America / USA, Europe / United Kingdom
Boundary conditions:
Engine test bench (operating point: 1500rpm @3,4bar IMEP, stoichiometric)
Typical gasoline E0 RON95 base fuel
Ethanol: E10, E20, E30, E50, E85, E100 splash blends with base fuel
Test vehicle/engine:
Single cylinder research engine, SI, 4V, spray-guided DI, 6-hole injector, centrally
mounted, displacement 565,6cm3, CR=11.5
Studies:
Indicated efficiency, HC, CO, NOx
Loading:
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[009.] Nakata K., Utsumi S., Ota A., Kawatake K., Kawai T., Tsunooka T.: The Effect
of Ethanol Fuel on a Spark Ignition Engine, Toyota Motor Corporation, SAE
International 2006-01-3380
Country:
Asia / Japan
Boundary conditions:
Engine test bench (two operating points: 2000rpm @2bar BMEP, 2800rpm @WOT,
stoichiometric)
Gasoline A: RON92 – US regular gasoline
Gasoline B: RON100 – Japanese premium gasoline as reference fuel
Ethanol: E10, E20, E50, E100 splash blends with gasoline A
Test vehicle/engine:
Toyota Corolla engine (1NZ-FE), Inline-4, displacement 1496cm3, CR=13, 4V, MPI
Studies:
Thermal efficiency, FC, THC, CO2, NOx
Loading:
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[010.] Szybist J., Foster M., Youngquist A., et. al.: Investigation of Knock Limited
Compression Ratio of Ethanol Gasoline Blends, Oak Ridge National
Laboratory, Delphi Powertrain Systems, SAE International 2010-01-0619
Country:
North America / USA
Boundary conditions:
Engine test bench
Fuels:
- Regular gasoline (RG): certification gasoline (UTG-91)
- High octane gasoline (HO): certification gasoline (UTG-96)
- Ethanol Blends: (RG & E100 mixed) E10, E50, E85
Test vehicle/engine:
Single-cylinder-engine: VVA, SI, DI, NA, 4V, CR=9.2, 11.85, 12.87
Studies:
Varied CR from 9.2 to 12.87.
Higher CR for Ethanol-Blends to examine high-load knock-limits
Loading:
0,8
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[011.] Bielaczyc P., Woodburn J., Klimkiewicz D., Pajdowski P., Szczotka A.: An
examination of the effect of ethanol–gasoline blends' physicochemical
properties on emissions from a light-duty spark ignition engine, engine,
Elsevier – Fuel Processing Technology 107 (2013) 50-63
Country:
Europe / Poland
Boundary conditions:
Chassis dynamometer (NEDC)
Base fuel: typical European gasoline E5 according EN228
Ethanol: E10, E25, E50 splash blends with E0 (reference fuel)
Test vehicle/engine:
Unmodified European EU5 passenger car, displacement 1200cm 3, SI, 4V
Studies:
THC, CO, CO2, NOx, PN, PM, Ethanol, Toluene, NO, Carbonyls, Acetylene
Tailpipe- and pre-TWC- emissions
Loading:
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[012.] Najafi G., Ghobadian B., Tavakoli T., Buttsworth D.R., Yusaf T.F.,
Faizollahnejad M.: Performance and exhaust emissions of a gasoline engine
with ethanol blended gasoline fuels using artificial neural network, Elsevier –
Applied Energy 86 (2009) 630-639
Country:
Asia / Iran, Australia / Australia
Boundary conditions:
Engine test bench (operating points: 1000-5000rpm @WOT, stoichiometric)
Base fuel: unleaded gasoline E0RON85
Ethanol: E5(RON90), E10(RON92), E15(RON94), E20(RON100) splash blends with
E0 (reference fuel); bio-Ethanol from potato waste according ASTM Standard
Test vehicle/engine:
Kia 4 cylinder-inline engine, SOHC, 4V, SI, MPI, displacement 1200cm3, CR=9.7,
47kW @5200rpm, 103Nm @2750rpm
Studies:
HC, CO, CO2, NOx
Loading:
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[013.] Koç M., Sekmen Y, Topgül T., Yücesu H.S.: The effects of ethanol–unleaded
gasoline blends on engine performance and exhaust emissions in a sparkignition engine, Elsevier – Renewable Energy 34 (2009) 2101-2106
Country:
Europe / Turkey
Boundary conditions:
Engine test bench (operating points: 1500-5000rpm @WOT, stoichiometric)
Base fuel: unleaded gasoline E0. Ethanol: E20, E85 splash blends with base fuel
Test vehicle/engine:
Hydra research single cylinder engine, PFI, SI, CR=10, 11, displacement 449cm3,
15kW @5400rpm,
Studies:
FC, CO, HC, NOx
Loading:
0,6
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[014.] Weinowski R., Sehr A., Rütten O., Thewes M., Nijs M.: Einfluss des
Ethanolanteils im Kraftstoff auf das Betriebsverhalten von PKW-Ottomotoren,
17. Aachener Kolloquium Fahrzeug- und Motorentechnik 2008
Country:
Europe / Germany
Boundary conditions:
Engine test bench (operating points: 2000rpm @3bar/9bar, stoichiometric)
Base fuel: unleaded gasoline E0(RON95)
Ethanol: E10, E20, E40, E60, E85 splash blends with base fuel
Test vehicle/engine:
4 cylinder-inline engine, 4V, SI, TC, DI, displacement 1800cm 3, CR=9.8, calibrated to
operate as flex-fuel
Studies:
Efficiency, HC, NOx, cold start
Loading:
1,0
[015.] Topgül T., Yücesu H.S., Cinar C., Koca A.: The effects of ethanol–unleaded
gasoline blends and ignition timing on engine performanceand exhaust
emissions, Elsevier – Renewable Energy 31 (2006) 2534-2542
Country:
Europe / Turkey
Boundary conditions:
Engine test bench (operating points: 2000rpm @WOT, stoichiometric)
Base fuel: unleaded gasoline E0 (RON99)
Ethanol: E10, E20, E40, E60 splash blends with base fuel
Test vehicle/engine:
Hydra research single cylinder engine, PFI SI, CR=8, 9, 10, displacement 449cm 3,
15kW @5400rpm,
Studies:
FC, CO, HC,
Loading:
0,6
[016.] Hsieh W., Chen R., Wu T., Lin T.: Engine performance and pollutant emission
of an SI engine using ethanol–gasoline blended fuels; Elsevier – Atmospheric
Environment 36 (2002) 403-410; Department of Mechanical Engineering,
National Cheng-Kung University & Southern Taiwan University of Technology,
Taiwan, 2001
Country:
Asia / Taiwan
Boundary conditions:
Engine test bench
Fuels:
E0 (ROZ 95)
E5, E10, E20, E30
Test vehicle/engine:
Engine: MPI, NA, CR=9.5, original ECU, 4V
Studies:
Emissions: CO2, CO, HC, NOx
Loading:
0,3
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[017.] Schifter I., Diaz L., Rodriguez R., Gómez J.P., Gonzalez U.: Combustion and
emissions behavior for ethanol–gasoline blends in a single cylinder engine,
Elsevier – Fuel 90 (2011) 3586–3592
Country:
North America / Mexico
Boundary conditions:
Engine test bench (operating points: 2000rpm @5,7bar, varying AFR)
Base fuel: unleaded gasoline E0(RON91) according ASTM standards
Ethanol: E6, E10, E15, E20 splash blends with base fuel
Test vehicle/engine:
Single cylinder engine by AVL model 5401, SI, DOHC, 4V, CR=10.5, displacement
500cm3, 25kW @6000rpm,
Studies:
FC, CO, HC, NOx
Loading:
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[018.] Yücesu H.S., Topgül T., Cinar C., Okur M.: Effect of ethanol–gasoline blends
on engine performance and exhaust emissions in different compression ratios,
Elsevier – Applied Thermal Engineering 26 (2006) 2272-2278
Country:
Europe / Turkey
Boundary conditions:
Engine test bench (Operating points: 2000, 3500, 5000rpm @WOT, stoichiometric)
Base fuel: unleaded gasoline E0 (RON99) according ASTM standards
Ethanol: E10, E20, E40, E60 splash blends with base fuel
Test vehicle/engine:
Hydra research single cylinder engine, PFI SI, CR=8-13 displacement 449cm3, 15kW
@5400rpm,
Studies:
FC, CO, HC,
Loading:
0,6
[019.] Hsieh W.-D., Chen R.-H., Wu T.-L., Lin t.-H.: Engine performance and
pollutant emission of an SI engine using ethanol–gasoline blended fuels,
Elsevier – Atmospheric Environment 36 (2002) 403-410
Country:
Asia / Taiwan
Boundary conditions:
Engine test bench (operating points: 3000rpm @20%WOT, WOT)
Base fuel: unleaded gasoline E0(RON95) according ASTM standards
Ethanol: E5, E10, E20, E30 splash blends with base fuel
Test vehicle/engine:
Commercial engine – new Sentra GA16DE, SI, DOHC, 4V, CR=9.5, displacement
1600cm3,
Studies:
FC, CO2, CO, HC, NOx
Loading:
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[020.] Nakama K., Kusaka J., Daisho Y.: Effect of Ethanol on Knock in Spark Ignition
Gasoline Engines, SAE-Paper: 2008-32-0020, 2008, Japan
May 2014
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Country:
Asia / Japan
Boundary conditions:
Engine test bench: single cylinder engine (operating points: 1500, 2000, 3000,
4000 rpm @ partial & full load)
Fuels: Reference Fuel (E0): RON 91 (55% iso-octane, 15% normal heptane, 30%
toluene)
Ethanol: reference fuel blended with absolute Ethanol (RON 108) to E3, E10, E20,
E40, E60, E80, E100
Test vehicle/engine:
Single-Cylinder Engine, 4V, PFI, 325 cm3, CR=9.5, 11.0, 13.9, 15.0
Studies:
BSFC, Brake Thermal Efficiency, E0 – E100
Loading:
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[021.] Knoll K., West B., Orban J., et. al.: Effects of Mid-Level Ethanol Blends on
Conventional Vehicle Emissions, SAE International, SAE: 2009-01-2723,
2009, USA
Country:
North America / USA
Boundary conditions:
Chassis dynamometer (LA 92 drive cycle, also known as Unified Cycle)
Fuels:
E0: certification gasoline (Indolene)
Splash blends with E0: E10, E15, E20
Test vehicle/engine:
16 conventional vehicles (model year: 1999 – 2007)
Studies:
NMOG, NMHC, CO, NOx, Fuel Economy, Ethanol, Aldehyde
Loading:
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[022.] Celik M.B.: Experimental determination of suitable ethanol–gasoline blend rate
at high compression ratio for gasoline engine, Elsevier – Applied Thermal
Engineering 28 (2008) 396-404
Country:
Europe / Turkey
Boundary conditions:
Engine test bench (operating points: 2000rpm @WOT, stoichiometric)
Base fuel: unleaded gasoline E0
Ethanol: E25, E50, E75, E100 splash blends with base fuel
Test vehicle/engine:
Lombardini LM250 single cylinder, Si, carburator, displacement 250cm 3, CR=6
Studies:
BSFC, CO2, CO, HC, NOx
Loading:
0,4
[023.] Masum B.M., Masjuki H.H., Kalam M.A., Rizwanul Fattah I.M., Palash S.M.,
Abedin M.J.: Effect of ethanol–gasoline blend on NOx emission in SI engine,
Elsevier – Renewable and Sustainable Energy Reviews 24 (2013) 209-222
Country:
Asia / Malaysia
May 2014
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Boundary conditions:
detailed literature review
Ethanol: E5, E10, E15, E20
Test vehicle/engine:
Studies:
NOx
Loading:
1
[024.] Kumar A., Khatri D.S., Babu M.K.G: An Investigation of Potential and
Challenges with Higher Ethanol-gasoline Blend on a Single Cylinder Spark
Ignition Research Engine, SAE International 2009-01-0137
Country:
Asia / India
Boundary conditions:
Engine test bench (operating points: 1500, 2000rpm @WOT, stoichiometric)
Base fuel: unleaded gasoline E0 (RON95)
Ethanol: E10, E30, E70 splash blends with base fuel
Test vehicle/engine:
AVL single cylinder research engine, displacement 500cm3, CR=10
Tests were carried out with and without modifications to the ECU (DOI, ignition
timing)
Studies:
CO, HC, NOx
Loading:
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[025.] Chen L., Stone R., Richardson D.: A study of mixture preparation and PM
emissions using a direct injection engine fuelled with stoichiometric
gasoline/ethanol blends, Elsevier – Fuel 96 (2012) 120–130
Country:
Europe / United Kingdom, Asia / China
Boundary conditions:
Engine test bench (Operating points: 1500rpm @0,5bar MAP and 20°C and 80°C
coolant temperature, SOI=280°CAbTDC, stoichiometric)
Base fuel: unleaded gasoline E0 (RON95)
Ethanol: E10, E20, E50, E70, E85 splash blends with base fuel
Test vehicle/engine:
Optical single cylinder research engine, displacement 562cm3, CR=11, 4V, DISI
Studies:
PM, PN, particle size distribution
Loading:
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[026.] Yüksel F., Ceviz M.A.: Effects of ethanol–unleaded gasoline blends on cyclic
variability and emissions in an SI engine, Elsevier – Applied Thermal
Engineering 25 (2005) 917-925
Country:
Europe / Turkey
Boundary conditions:
Engine test bench (operating points: 2000rpm @WOT, MBT timing, rich)
Base fuel: unleaded gasoline E0
Ethanol: E5, E10, E15, E20 splash blends with base fuel
May 2014
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Test vehicle/engine:
Fiat engine, displacement 1581cm3, carburator, CR=9,2, SI, 4-stroke
Oil-temperature=50°C, coolant temperature=70°C, 62kW@5800rpm
Studies:
CO, HC, NOx
Loading:
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[027.] Karavalakis G., Short D., Hajbabaei M., Vu D., Villela M., Russel R., Dubin T.,
Asa-Awuku A.: Criteria Emissions, Particle Number Emissions, Size
Distributions, and Black Carbon Measurements from PFI Gasoline Vehicles
Fuelled with Different Ethanol and Butanol Blends, SAE International 2013-011147
Country:
North America / USA
Boundary conditions:
Chassis dynamometer (FTP-75, UC)
Base fuel: E10 RON93
Ethanol: E15, E20
Test vehicle/engine:
Three light duty vehicles with TWC
2007 Honda Civic 1.8l, 4-cylinder, PFI (BIN5/ULEV)
2007 Dodge Ram 5.7l, 8-cylinder, PFI (BIN4/LEV2)
2012 Toyota Camry 2.5l, 4-cylinder, PFI (BIN5/PZEV)
Studies:
THC, NMHC, CH4, CO, NOx, CO2, Fuel economy, Carbonyls, PN, Black Carbon
Loading:
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[028.] Stein R.A., Anderson J.E., Wallington T.J.: An Overview of the Effects of
Ethanol-Gasoline Blends on SI Engine Performance, Fuel Efficiency, and
Emissions, SAE International 2013-01-1635
Country:
North America / USA
Boundary conditions:
Very detailed study on the use of ethanol in modern SI engines
Chassis dynamometer (FTP-phase1)
Test vehicle/engine:
7 passenger cars (1x MY2006, 6x MY2007 FFV‘s)
Ethanol: E6, E32, E59, E85
Studies:
Carbonyls, Benzene
Loading:
1
[029.] Storey J.M., Barone T., Norman K., Lewis S.: Ethanol Blend Effects on Direct
Injection Spark-Ignition Gasoline Vehicle Particulate Matter Emissions, SAE
International 2010-01-2129
Country:
North America / USA
Boundary conditions:
Chassis dynamometer (FTP-75, US06)
Base fuel: E0 (RON97) as Federal certification fuel
Ethanol: E10, E20 splash blends with base fuel (supplier: Gage products)
May 2014
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Test vehicle/engine:
US legal stoichiometric turbocharged DISI vehicle (2007 Pontiac Solstice,
displacement 2l)
Studies:
NMHC, CO, NOx, fuel economy, carbonyls, benzaldehyde, PM
Loading:
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[030.] Delgado R., Paz S.: Effect of Different Ethanol-Gasoline Blends on Exhaust
Emissions and Fuel Consumption, SAE International 2012-01-1273
Country:
Europe / Spain
Boundary conditions:
Chassis dynamometer (NEDC)
Base fuel: E0 (RON96)
Ethanol: E5 splash blend with base fuel, E10 (RON97), E85 (RON107)
Test vehicle/engine:
Two test vehicles
EU4 E10-vehicle (investigations: E0, E5splash, E10), displacement 1,4l
EU4 FFV-vehicle (investigations: E0, E85), displacement 1,8l
Studies:
THC, NMOG, CH4, CO, NOx, CO2, fuel consumption, carbonyls, PM, ethanol
Loading:
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[031.] He B., Wang J., Hao J., Yan X., Xiao, J.: A study on emission characteristics
of an EFI engine with ethanol blended gasoline fuels, Elsevier –Atmospheric
Environment 37, S. 949-957, 2002
Country:
Asia / China
Boundary conditions:
Engine test bench with catalyst, different load points (idle to WOT)
Base fuel: E0 (RON92)
Ethanol: E10, E30 splash blends with base fuel
Test vehicle/engine:
MPI, NA, CR=8,2
Studies:
Engine-out & Tailpipe: THC, NOx, CO, BSFC, BSEC, Ethanol, Acetaldehyde
Loading:
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[032.] Bäcker H., Tichy M., Achleitner E., Pischinger S., Lang O., Habermann K.,
Kreber-Hortmann K.: Untersuchung des Ethanolmischkraftstoffs E85 im
geschichteten und homogenen Magerbetrieb mit piezoaktuierter A-Düse
Country:
Europe / Germany
Boundary conditions:
Single Cylinder Engine, E0 and E85
Test vehicle/engine:
Single Cylinder Engine (Siemens), displacement 500cm3, DI, NA, 4V, central Position
Injector and Spark Plug
Studies:
HC, NOx, CO, Smoke Number @ 2000 rpm, λ=1 for IMEP=2,7bar and WOT
May 2014
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Loading:
1,0
[033.] List R., Hofmann P., Urbanek M.: The effects of Bio-Ethanol Mixtures on the
SI-Engine Operation, Vienna University of Technology
Country:
Europe / Austria
Boundary conditions:
Engine Test Bench @ 2 part load points
Base Fuel: unleaded gasoline (RON95)
Splash Blends: E10, E50, E85, E100
Test vehicle/engine:
MPFI
Studies:
HC, CO, NOx, BSFC, BSEC @ 2000rpm/2bar and 4000rpm/5bar
Loading:
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[034.] Wallner T., Ickes A., Lawyer K., Ertl D., Williamson R.: Higher Alcohols in
Multi-Component Blends with Gasoline – Experimental and Analytical
Assessment, 14. Tagung: “Der Arbeitsprozess des Verbrennungsmotors”, 24.25. September 2013, Graz
Country:
North America / USA
Boundary conditions:
Engine Test Bench @ 5 load points
Base Fuel: certification gasoline (EEE) RON 97,1
Ethanol: E50, E77 (splash blends with EEE)
Test vehicle/engine:
NA, DI, 2,36ccm, CR=11,3 (Hyundai Theta II)
Studies:
Efficiency, Fuel Consumption, CO2, CO, NOx, HC @ 1500rpm/2,62bar, 4bar, 8bar,
3000rpm/4bar, 8bar
Loading:
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[035.] i L., Liu Z., Wang H., Deng B., Xiao Z., Wang Z., Gong C., Su Y.: Combustion
and Emission of Ethanol Fuel (E100) in a small SI Engine, SAE 2003-01-3262
Country:
Asia / Shanghai
Boundary conditions:
Engine Test Bench @ different air fuel ratio, different rpm, different load
Base Fuel: Gasoline, E100 (100% Ethanol)
Test vehicle/engine:
Four stroke, air cooled 125cc SI engine for motorcycles with a single point electronic
gasoline fuel injection system modified with an ethanol fuel injection system
Studies:
The effect of fuel injection duration, spark timing, excess air/fuel ratio on engine
power output, fuel and energy consumption, engine exhaust emission levels
Loading:
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[036.] Oh H., Bae C., Min K.: Spray and Combustion Characteristics of Ethanol
Blended Gasoline in a Spray Guided DISI Engine under Lean Stratified
Operation, SAE International 2010-01-2152
May 2014
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Country:
Asia / Korea
Boundary conditions:
Engine test bench (Operating point: 1200rpm @ EOI-var and 80°C coolant
temperature, no EGR, constant energy of 473,5 J/stroke, EOI=2°CA before
first misfire occur)
Base fuel: unleaded gasoline E0 (RON96,4)
Ethanol: E25, E50, E85 splash blends with base fuel
Test vehicle/engine:
Single cylinder, spray guided DISI, CR=12, central mounted piezo injector,
displacement 499cm3
Studies:
Combustion efficiency, HC, NOx, FSN
Loading:
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[037.] Gogos M., Savvidis D., Triandafyllis J.: Study of the Effects of Ethanol Use on
a Ford Escort Fitted with an Old Technology Engine, SAE International 200801-2608
Country:
Europe / Greek
Boundary conditions:
Chassis dynamometer @ different speeds (30, 50, 90km/h) @ WOT
Base Fuel: LRP (Lead Replacement Petrol)
Ethanol: E10, E20, E50 splash blends
Test vehicle/engine:
Ford Escort 1.3, odometer reading 170000km, 4 Cylinders, 1297ccm, CR=9,3
Studies:
FC, SFC, NOx, CO, CO2, O2, HC
Loading:
0,6 (Car without Close-Loop Lambda controller)
[038.] Nematizade P., Ghobadian B., Ommi F., Najafi G.: Performance and exhaust
emissions of a spark ignition engine using G-Series and E20 fuels,
International Journal of Automotive Engineering and Technologies, ISSN
2146-9067, 2013
Country:
Asia / Iran
Boundary conditions:
Engine test bench (WOT from 2000rpm to 4000rpm)
Base fuel: Gasoline
Ethanol: E20 splash blend (20v% Ethanol and 80v% Base fuel)
Test vehicle/engine:
4 cylinder engine, CR=9,25, Displacement=1761ccm
Studies:
FC, SFC, HC, CO, CO2
Loading:
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[039.] Beer T., Grant T.: Life-cycle analysis of emissions from fuel ethanol and
blends in Australian heavy and light vehicles, Journal of Cleaner Production
No. 15 (2007), 833-837
Country:
Australia / Victoria
May 2014
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Boundary conditions:
Literature study
Base fuel: Gasoline (Premium unleaded petrol)
Ethanol: E10, E85
Studies:
CO2, PM10, NOx, HC, CO
Loading:
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[040.] Urbanek M., Hofmann P., Geringer B.: Vehicle use of ethanol blends –
Emission performance and potential for CO2-Reduction, 12th EAEC European
Automotive Congress Bratislava, 2009
Country:
Europa / Austria
Boundary conditions:
Chassis dynamometer (NEDC, CADC)
Base fuel: RON95
Ethanol: E5, E10, E85, E100
Test vehicle/engine:
Conventional and Flex Fuel Vehicles
Studies:
HC, CO, NOx, CO2
Loading:
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[041.] Pang X., Mu Y., Yuan J., He H.: Carbonyls emission from ethanol-blended
gasoline and biodiesel-ethanol-diesel used in engines, Atmospheric
Environment 42 P. 1349-1358, 2008
Country:
Asia / China
Boundary conditions:
Engine Test bench (different load points: WOT @ 1200-2800 and 1800 @ different
loads)
Base fuel: RON93 (Chinese Market)
Ethanol: E10
Test vehicle/engine:
4 Cylinder, 1.993 ccm, CR=9,5, 76 kW, 155 Nm
Studies:
HC, CO, NOx, SFC
Loading:
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[042.] Eichelseder H., Grabner P., Eckhard G..: Potential of E85 Direct Injection for
Passenger Car Application, FVV Frühjahrstagung 2012, Bad Neuenahr 2012
Country:
Europa / Austria
Boundary conditions:
Single Cylinder Research Engine
E0 (RON95), E85
Test vehicle/engine:
Single Cylinder Test Engine, CR=9 to 13.5
Studies:
HC, CO, NOx, PM, PN
May 2014
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Loading:
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[043.] Song C., Zhang W., Pei Y., Fan G., Xu G.: Comparative effects of MTBE and
ethanol additions into gasoline on exhaust emissions, Atmospheric
Environment 40 P. 1957-1970, 2006
Country:
Asia / China
Boundary conditions:
Engine test bench /various loads and speeds)
Base Fuel: RON92,5
Ethanol: E2, E5, E7, E10
Test vehicle/engine:
4 Cylinder, PFI, CR=7,6
Studies:
CO, HC, NOx, Benzene, Aldehyde
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[044.] Jung H., Shelby M., Newman C., Stein R.: Effect of Ethanol on Part Load
Thermal Efficiency and CO2 Emissions of SI Engines, SAE International 201301-0254
Country:
North America / USA
Boundary conditions:
Engine Test bench (1500 & 2000 rpm @ Part Load) @ λ=1
Base Fuel: RON90.1
Ethanol: E85
Test vehicle/engine:
V8, Turbo, DI, VCT, 4951ccm, CR = 9,5
Studies:
BTE, BSFC, CO, HC, CO
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[045.] Sandquist H., Karlsson M., Denbratt I.: Influence of Ethanol Content in
Gasoline on Speciated Emissions from a Direct Injection Stratified Charge SI
Engine, SAE International 2001-01-1206
Country:
Europe / Sweden
Boundary conditions:
Engine Test bench (1000, 2000, 3000rpm @ Part Load)
Base Fuel: RON95
Ethanol: E5, E10, E15
Test vehicle/engine:
4 Cylinder, DI, CR=12,5, 1834ccm
Studies:
HC, Smoke, NOx, CO, SFC, Acetaldehyde, Formaldehyde, Ethanol
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[046.] Al-Farayedhi A., Al-Dawood A., Gandhidasan P.: Effects of Blending Crude
Ethanol with Unleaded Gasoline on Exhaust Emissions of SI Engine, SAE
International 2000-01-2857
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Country:
Asia / Saudi Arabia
Boundary conditions:
Engine Test bench (
Base Fuel: RON85
Ethanol: E10, E15, E20
Test vehicle/engine:
6 Cylinder, 2960ccm, CR=9,2
Studies:
CO, HC, NOx
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[047.] Urbanek M.: Der Einfluss von flüssigen und gasförmigen alternativen
Kraftstoffen auf die Emissionen von Kraftfahrzeugen bei der ottomotorischen
Verbrennung, Dissertation TU Wien Institut für Fahrzeugantriebe und
Automobiltechnik, 2010
Country:
Europe / Austria
Boundary conditions:
Chassis dynamometer (various vehicles (conventional and Flex Fuel)
Base Fuel: RON95
Ethanol: E5, E10, E20, E50, E65, E85
Test vehicle/engine:
Various vehicles (conventional and Flex Fuel
Studies:
CO, HC, NOx, CO2
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[048.] List R.: Potenzialbewertung von Benzin-Ethanol Kraftstoffmischungen im
ottomotorischen Betrieb, Disserttation TU Wien Institut für Fahrzeugantriebe
und Automobiltechnik, 2008
Country:
Europe / Austria
Boundary conditions:
Engine test bench (one PFI and one DI engine)
Base Fuel: RON95
Ethanol: E10, E20, E50, E85, E100
Test vehicle/engine:
4 Cylinder, PFI, 1598ccm, CR=10,5
4 Cylinder, DI, Turbo, 1396ccm, CR=10,0
Studies:
SFC, SEC, CO, NOx, HC
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[049.] Teiner P.: Potenzialvergleich der Laserzündung zur Funkenzündung beim
Einsatz von Ethanolkraftstoffen in einem 1-Zylinder Ottomotor, Diplomarbeit
TU Wien Institut für Fahrzeugantriebe und Automobiltechnik, 2007
Country:
Europe / Austria
Boundary conditions:
Engine Test bench
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Base Fuel: RON95
Ethanol: E5, E10, E22, E50, E85, E100
Test vehicle/engine:
1 Cylinder Research Engine, CR=11,12, 512ccm
Studies:
CO, HC, NOx
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[050.] Dedl P., Hofmann P., Geringer B., Karner D., Lohrmann M.: Suitability and
Potential of Alternative Fuels fort he Use in Spark Ignition Engines, 8th
International Colloquium for Fuels, 2011
Country:
Europe / Austria
Boundary conditions:
Chassis dynamometer
Base Fuel: RON95
Ethanol: E10, E25, E50
Test vehicle/engine:
Conventional vehicle equipped with turbocharged, direct fuel injection engine
Studies:
HC, CO, CO2, FC
Loading:
1,0
[051.] Yao Y., Tsai J., Wang I.: Emissions of gaseous pollutant motorcycle powered
by ethanol-gasoline blend, Applied Energy 102 P. 93-100, 2013
Country:
Asia / Taiwan
Boundary conditions:
Chassis dynamometer (two motorcycles equipped with carburettor and PFI)
Base Fuel: RON95
Ethanol: E10, E15, E20, E30
Test vehicle/engine:
two motorcycles equipped with carburettor and PFI, 125ccm
Studies:
CO, HC, NOx
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[052.] Graham L., Belisle S., Baas C.: Emissions from light duty gasoline vehicles
operating on low blend ethanol gasoline and E85, Atmospheric Environment
42 P. 4498-4516, 2008
Country:
North America / Canada
Boundary conditions:
Chassis dynamometer (four-phase implementation of the FTP was used)
Base Fuel: RON86
Ethanol: E10 tailor blend, E20 tailor blend and E10 splash blend
Test vehicle/engine:
2002 Chrysler Caravans, 2004 Chrysler Sebrings
Both are equipped with Flex Fuel technology
Studies:
CO, NOx, HC, Benzene, Acetaldehyde, Formaldehyde
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7.2 Further literature
Referenced in the text in parentheses.
1. Borenstein, M., et al. Introduction to Meta-Analysis. s.l. : John Wiley & Sons, Ltd.
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Teubner, 2. Auflage 2008. ISBN 978-3-8348-0445-7.
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Springer-Verlag, 2005. ISBN 3-540-23883-2.
5. Martin, C. Innovative Zündsysteme für hochaufgeladene Downsizingmotoren,
Diplomarbeit am IFA, TU-Wien. Wien : s.n., Dezember 2011.
6. Korte, V., et al. Effizientes Downsizing für zukünftige Ottomotoren. s.l. : MTZ Motortechnische Zeitschrift, 05/2011 72.Jahrgang.
7. Geringer, B. Verbrennungskraftmaschinen Grundzüge. Skriptum zur Vorlesung.
TU Wien : s.n., 2006.
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9.
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bei Ottomotoren
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Vorentflammungen. s.l. : MTZ - Motortechnische Zeitschrift, Jahrgang 70, 05/2009.
10. Dedl, P., Hofmann, P. and Geringer, B. Untersuchung des Volllastpotenzials
unterschiedlicher Alkoholkraftstoffe für den ottomotorischen Einsatz im MPFI
Saugmotor
und
DI
Turbomotor.
13.
Tagung
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Arbeitsprozess
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14. Bobicic, N., et al. Einfluss von Ethanolkraftstoff auf die Vorentflammungsneigung
von hochaufgeladenen Ottomotoren. Tagung Berlin, Ottomotorisches Klopfen,
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16. Hamilton, L. J., et al. Pre-Ignition Characteristics of Ethanol and E85 in a Spark
Ignition engine. U.S. Naval Academy : SAE, 2008-01-0321.
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